I looked around some more just because. The JDL is a liberal organization and they were not finding fault with a comment made by Bridget Gabriel (who stated that it is between 15 and 25% of Muslims who are involved in terrorism), they were more finding fault with Gabriel herself for being conservative.
Bridget Gabriel was born in Lebanon. When she was 14 or 15 years old Palestinians invaded Lebanon and blew up her house. She and her family survived the attack, she was in the hospital for 2 months. They ended up living bomb shelter. She had to either ride in a tank to go to school or make a dash for it. She is not Jewish, she is a Christian. She ended up moving to Israel and married an American and now lives in America, probably in your backyard in NYC.
However, I found a Pew Research survey on American Muslims. 66% say they are "very concerned" about Islamic extremism. 16% say they are somewhat concerned. That leaves 18% which are either somewhat not concerned or not at all concerned.
This is not an indication of support for terrorism, this is just what they are concerned about. They can be concerned and still want to kill all Jews. Concerned is somewhat vague, so is "Islamic extremism". Considering how many times Muslims are commanded to kill the unbelievers, mainstream Islam are the ones who want to kill you. There are no extremists, there are those who passively follow Islam, and that is the majority. Muslims do not spend a lot of time reading the Quran, on average. So a whole lot of them don't even know they are commanded to kill the unbeliever.
Oh wait.... I forgot for a second who I was talking to. You haven't even read this far because I lost you after "I looked...". Buh bye.